Thyrotoxicosis and a neck lump in a 34-year-old
History
34-year-old woman with palpitations and weight loss. TSH below 0.01 mU/L, free T4 26 pmol/L, free T3 9.8 pmol/L; TSH-receptor antibodies negative. A 3 cm right-sided neck nodule is palpable; no eye signs. On propranolol only. She has a 2-year-old son, is not breastfeeding, and would like definitive treatment. Request: thyroid scintigraphy and advice on ¹³¹I.
Step 1 · Thyroid scan
The pinhole image shows a single intensely avid nodule in the right lobe; the rest of the gland is barely visible. What is the diagnosis?